Electrical connecting device



Aug. 4, 196 J. A. ZIMMERMAN, JR., ETAL 3,143,385

ELECTRICAL CONNECTING DEVICE 3 Sheets-Sheet 1 Filed May 14, 1962ELECTRICAL CONNECTING DEVICE 3 Sheets-Sheet 2 Filed May 14, 1962 n on 33? 2L g- 1964 J. A. ZIMMERMAN, JR., ETAL 3,143,385.

ELECTRICAL CONNECTING DEVICE United States Patent 3,143,385 ELECTRICALCONNECTING DEVICE John A. Zimmerman, Jr., Hershey, and Frank B.h/Iiller, J12, Mechanicshurg, Pa, assignors to Al /H Incorporated,Harrisburg, Pa.

Filed May 14, 1962, Ser. No. 194,369 6 Claims. (Cl. 339217) Thisinvention relates to electrical connecting devices of the typecomprising a contact terminal which is contained Within an insulatinghousing.

A common type of electrical connecting device for disengageablyconnecting electrical conductors comprises a pair of insulating blocks,each of which has a plurality of contact terminals therein so that whenthe blocks are engaged with each other the contact terminals of eachblock are mated with terminals in the other block. One type of contactterminal used in these multi-contact connectors is adapted to be crimpedor otherwise secured to the end of a wire and subsequently inserted intoa cavity in the insulating block. With this type of contact terminal, itis necessary to provide a means for retaining the terminal in theinsulating block after insertion and preventing its accidental orunauthorized removal from the cavity. At the same time, it isadvantageous to have the contact terminal removable from the cavity forpurposes of replacement, repair, or to permit changes in circuitry. Theinstant invention relates to these insertable types of electricalcontacts which are used in multi-contact connecting devices.

An object of the invention is to provide an improved retaining means forretaining an electrical contact terminal in a cavity. A further objectis to provide an improved retaining means which is disposed within thecavity in the insulating block rather than on the contact. A stillfurther object is to provide a retaining means which positively holdsthe contact in the cavity and prevents removal excepting when aspecialized tool is used for the purpose. A still further object is toprovide a substantially fool-proof retaining means which is not prone todamage in normal usage.

These and other objects of the invention are achieved in a preferredembodiment comprising a split cylindrical sleeve having a pair offorwardly extending arms on one end. The ends of these arms are enlargedand extend arcuately around the axis of the split sleeve. The lateraledges of the enlarged ends of the arms are inwardly bent towards thesleeve axis to form lips or flanges. The retaining device of the instantinvention is intended to be used with an insulating block having agenerally cylindrical cavity extending therethrough and in which thereare provided a pair of opposed arcuate bosses. The retainer is disposedin the cavity with the edge of the split sleeve disposed against thebosses on one side thereof and with the arms extending between thebosses so that the enlarged ends of the arms extend circumferentiallypartially around the cavity at the opposite end of the bosses. Theinwardly bent lips on the ends of the arms normally project radiallyinwardly towards the center of the cavity some what beyond the surfacesof the bosses so that when an electrical contact having acircumferential recess therein is positioned in the cavity with the lipsor flanges extending into the recess of the contact, the terminalcontact can not be withdrawn by virtue of the wedging action of theflanges or lips of the retainer. The contact terminal can, however, beremoved from the cavity if the enlarged ends of the arms are spreadapart so that the inwardly turned lips or flanges do not project intothe circumferential recess in the contact terminal. Spreading of thearms of the retainer can, however, only be achieved by means of aspecial tool so that accidental removal or withdrawal of the contactfrom the cavity can not happen.

In the drawing:

FIGURE 1 is a perspective View of a type of contact terminal with whichthe retaining means of the instant invention is adapted to be used.

FIGURE 2 is a perspective view of a contact retaining means inaccordance with the invention.

FIGURE 3 is a sectional side view of the retaining means of FIGURE 2taken along the lines 33 of FIG- URE 4.

FIGURES 4 and 5 are views taken along the lines 4-4 and 5-5 of FIGURE 3.

FIGURE 6 is a sectional view showing a portion of a cavity in aninsulating block which is adapted to receive the retaining means ofFIGURE 2.

FIGURES 7 and 8 are views taken along the lines 77 and 38 of FIGURE 6.

FIGURE 9 is a view similar to FIGURE 6 but showing the retaining meanspositioned in the cavity.

FIGURE 10 is a view looking into the end of the cavity of FIGURE 9 takenalong the lines 1016 of FIG- URE 9.

FIGURES 11, 12 and 13 are views illustrating the insertion of thecontact of FIGURE 1 into the cavity; these views are not true sectionsbut are taken along the lines 11-11 of FIGURE 10 in the interest ofclarity.

FIGURE 14 is a view illustrating the manner in which the contact isremoved from the cavity in the insulating block.

FIGURE 15 is a fragmentary cross sectional view showing a pair ofcontacts in engagement with each other and showing the retaining meansof the instant invention as used with a socket contact; this view is nota true section but is similar to FIGURES 11-13.

A commonly known type of electrical contact terminal 2 with which theretaining device of the invention is adapted to be used is shown inFIGURE 1 to comprise a hollow cylindrical crimp portion 4, anintermediate collar 6, and a uniform diameter cylindrical section 8disposed forwardly of collar 6. A conical inwardly tapering surface It)is provided forwardly of the section 8 and this conical sectionterminates in a relatively sheer rearwardly facing shoulder 12 in frontof which there is a further cylindrical section 14 of the same diameteras the cylindrical section 8. A relatively steep conical surface 16extends from the cylindrical section 14 to the reduced diametercylindrical pin end section 18 of the contact. This end section isadapted to be received within complementary socket contact describedbelow. The crimp section 4 is axially bored to receive the stripped endof a conductor 22 to which it may be crimped as is shown at 2% in FIGURE14.

The complementary socket contact 24, as shown in FIGURE 15, has anaxially bored forward end for engagement with the projecting pin portion18 of the pin contact 2. The intermediate and rearward portions of thesocket contact have substantially the same external configuration as thepin contact 2 and need not be described in further detail. Thecorresponding portions or parts of tins socket contact are identified bythe same reference numerals as are used with respect to the pin contactbut differentiated by prime marks.

Contacts of the type shown at 2 and 24 are adapted to be crimped ontothe ends of conductors and then inserted into cavities in insulatingblocks. Ordinarily, a plurality of pin contacts 2 are inserted into oneblock and a like number of socket contacts 24 are inserted into anotherblock. When the two blocks are brought into engagement with each other,each of the individual pin contacts in the one block is mated with asocket contact in the other block. An exemplary type of insulating blockis shown fragmentarily in FIGURE 14 to comprise a relatively firmsection 26 and a relatively yieldable section 28, these two sectionsbeing either secured to each other by a suitable adhesive or heldagainst each other by means of a surrounding shell or frame. Therelatively hard portion 26 of the insulating block may be of anysuitable relatively hard moldable insulating material such as diallylphthalate while the resilient section 28 may be of a neoprene rubber.The two sections 26, 28 each have openings extending therethrough whichtogether define a cavity adapted to receive the pin contact after it hasbeen crimped onto the end of a wire.

The opening in the relatively firm and hard section 26 of the insulatingblock is cylindrical as shown at 32 in its forward section which opensinto the mating face 3%. At the rearward end of this firm section of theinsulating block the opening is also cylindrical at 34 but of a diametersomewhat less than the cylindrical section 32, the diameter of thecylindrical section 34 being slightly less than the diameter of thecollar 6 of the pin contact and approximately equal to the diameter ofthe portion 8 of the pin plus two times the metal thickness of theretainer as is apparent from FIGURE 11. A pair of bosses 36 are providedbetween the two cylindrical portions 34, 32 having arcuate surfaces 42and defining a forwardly facing shoulder 38 at the end of thecylindrical section 32 and a rearwardly facing shoulder 40 at the end ofthe cylindrical section 34.

The resilient portions of the composite housing 28 has a cylindricalopening 44 having a normal diameter which is substantially equal to thediameter of collar 6 of the contact. Opening 44 has a plurality ofinwardly extending collars 46 near its rearward end so that uponinsertion, the collars 46 will resiliently press against the surface ofthe wire to form an environmental seal for the contact. The forward end45 of the opening 44 is of a reduced diameter thereby to form a stop forthe collar 6 and to limit inward movement of the contact.

The retaining means 48 in accordance with the invention (FIGURE 2)comprises a split cylindrical sleeve 50 having a pair of opposed axiallyforwardly extending arms 52, the ends of which are enlarged at 54 toform arcuate cylindrical segments having the axis of the sleeve t) as acenter. The extreme end portions of the arms are somewhat flared at 56outwardly to facilitate the removal of a contact from the cavity in amanner described below. The edges of the enlarged ends 54 of the armswhich are opposed to the split sleeve 50 are inwardly turned to formradially inwardly directed lips or flanges 60 which flanges folow thearcuate cylindrical configuration of the enlarged end portions 54 of thearms. The inner surfaces of the arms are provided with protuberances 58in the form of dimples which function as camming means during insertionof the contact into the cavity.

The contact retainer of FIGURE 2 should be dimensioned in accordancewith the size of the contact and the cavity in the insulating blocksection 26. Specifically, the width of the enlarged ends 54 of the arms52, as measured along their arcuate surfaces, should be slightly lessthan the distance between the sides of the bosses 46 to permit insertionof the retaining means into the cavity.

The diameter of the split sleeve 50 should be slightly less than thediameter of the cylindrical portion 34 of the cavity in the relativelyhard insulating block 26.

The retaining means 48 is inserted into the cavity in the block portion26 prior to assembly of the two block portions 26, 28 to each other.Insertion is accomplished by axially aligning the retainer 48 with thecavity on the righthand side thereof as viewed in FIGURE 6 and with thearms 52 in rotational alignment with the surfaces 42 of the bosses.After aligning the retainer with the cavity in this manner, the retaineris inserted until the enlarged ends are disposed forwardly of theforward shoulder 38 in the cavity. Thereafter the retainer is rotateduntil the bosses extend into the spaces between the lips 60 and thesplit sleeve 50 as is shown in FIGURE 9. After such insertion androtation of the retainer, it can not move leftwardly from the positionof FIGURE 9 by virtue of the engagement between the split collar 50 andthe rearwardly facing shoulders 40 and rightward movement of theretainer is prevented by the inwardly turned lips which bear against theforwardly facing shoulders 38. It will be noted in this figure that thediarneter of the forward cylindrical section 32 of the cavity issubstantially greater than the diameter of the frontal end of theretainer at the flared sections 56 so that the retainer can be flexedoutwardly as is described below.

After insertion or assembly of the retainer to the forward cavitysection 26, the two block sections 26, 28 are secured to each other orclamped together as is described above. Thereafter, the contact, crimpedonto the end of a wire, is inserted axially through the resilientsection 28 of the cavity and through the retainer 48 in the relativelyfirm section of the block as shown in FIGURES 1113. As noted above inthe description of the figures of the drawing, FIGURES 11-13 are nottrue longitudinal cross sectional views but are taken along the lines1111 of FIGURE 10 and drawn to show a full elevation. The purpose ofthis type of view is to clearly show both the function of the lips 69and the function of the dimpies 58.

It will be noted from FIGURE 11 that the lips or flanges 69 normallyextend inwardly beyond the surfaces 42 of the bosses so that when theparts are in the position of FIGURE 11, these lips would tend to preventinsertion of the contact. At this stage, however, the conical surface 16on the forward end of the contact engages the dimples or bosses 56 sothat the arms 52 are cammed outwardly to the position of FIGURE 12. Whenthe parts are in the positions of their figure, the inner edges offlanges 60 are located radially beyond the surfaces 42 of the bosses.Upon further leftward movement of the contact from the position ofFIGURE 12 to the position of FIGURE 13, the arms are permitted to returnresiliently to their normal position and the bosses 58 will project intothe recess defined by the conical surface 10 and the shoulder 12. Thus,when the parts are in their normal positions after insertion of thecontact terminal, the lips 60 extend inwardly beyond surfaces 42 of thebosses and are disposed between the shoulders 38 of the bosses and theshoulder 12 of the contact terminal. If the wire to which the contactterminal is attached is pulled, the contact terminal will tend to moverightwardly in FIGURE 13 but will be prevented from movement by the lips60 which will be wedged between the shoulder 38 and the shoulder 12 ofthe contact. Withdrawal of the contact from the cavity is thus virtuallyimpossible so that application of extremely high withdrawal force to theconductor would result in destruction of the contact or the retainerrather than in the contact being removed from the cavity.

Forward movement of the contact beyond the position of FIGURE 13 isprevented by the collar 6 which compresses the reduced diameter portion45 of block 28 against hard portion 26. This compressed material assistsin establishing an environmental seal for the contacts.

Where it is desired to remove the contact from the cavity for purposesof repair, replacement, or changing the circuitry, a simple toolcomprising a tubular sleeve 62 and a plunger 64 is used as shown inFIGURE 14. The tool is inserted into the cavity from the mating faceuntil the bevelled edge of the tube 62 engages the inner surfaces of theflared ends of the contact. The arms 52 are flexed outwardly by the tubeso that upon subsequent rightward movement of the plunger 64, thecontact is pushed rightwardly from the cavity and past the inwardlydirected lips 60 which will have been moved out of the way of thecylindrical contact portion 14.

As is apparent from FIGURE 15, a retaining means in accordance with theinvention functions substantially in the same manner with the socketcontact 24 as with the pin contact of FEGURE 1. The forward end 25 ofthe socket contact is slightly tapered to facilitate insertion and toexert a camming action on the dimple 53 of the retainer.

A salient advantage of the invention is that the contacts can beretained in their cavities positively and securely in a manner such thataccidental removal is virtually impossible although intentional removalwhen de sired can be accomplished with relative ease and without damageto the contacts or to the retainer. Additionally, since the retainingmeans is contained within the cavity, the possibility of damage theretois avoided as is the case where the retaining means are provided on thecontact.

Changes in construction will occur to those skilled in the art andvarious apparently different modifications and embodiments may be madewithout departing from the scope of the invention. The matter set forthin the foregoing description and accompanying drawings is offered by wayof illustration only. The actual scope of the invention is intended tobe defined in the following claims when viewed in their properperspective against the prior art.

We claim:

1. Electrical connecting means comprising, an insulating housing havinga generally cylindrical cavity extending therethrough, a generallycylindrical contact retainer disposed in said cavity, said retainerhaving an opening intermediate its ends, a boss in said cavity extendinginto said opening thereby to provide interlocking means for holding saidretainer in said cavity, said retainer having an inwardly directed lipdisposed forwardly of said boss and extending radially inwardly beyondsaid boss, and an inwardly directed protuberance on said retainerbetween the rearward end thereof and said lip, said cavity being adaptedto receive an electrical contact having a rearwardly facing shoulderintermediate its ends and having a camming surface in front of saidshoulder whereby, upon insertion of said contact into said cavity, saidcamming surface contacts said protuberance and said lip is forcedradially outwardly to permit passage of said shoulder beyond said lip,and subsequently said lip returns to its normal position and is disposedbetween said boss and said shoulder to restrain said contact againstwithdrawal.

2. A device as set forth in claim 1 wherein said retainer comprises asplit sleeve having at least one arm axially therefrom, an enlarged endon said arm, the space between said enlarged end and said sleeveconstituting said opening, and said lip extending from said enlargedend.

3. A device as set forth in claim 1 wherein said retainer comprises asplit cylindrical sleeve having an arm extending axially therefrom, anenlarged end on said arn, said sleeve being disposed on one side of saidboss and said enlarged end being disposed on the other side of saidboss, said lip extending from said enlarged end, and said protuberancebeing provided on said arm intermediate the ends thereof.

4. Electrical connecting means comprising, an insulating body having acylindrical cavity therein, a pair of opposed bosses in said cavityintermediate the ends thereof, said bosses having arcuate surfacesextending generally parallel to the walls of said cavity and each bosshaving a shoulder facing forwardly of said cavity, contact retainingmeans in said cavity comprising a cylindrical sleeve having axiallyextending arms on one end, said sleeve being disposed on one side ofsaid bosses and said arms extending between said bosses, enlargedarcuate ends on said arms extending circumferentially around said cavityin front of said bosses, said enlarged ends each having an inwardlyturned lip in front of and opposed to said shoulders, said lips normallyextending radially inwardly beyond said arcutate surfaces of saidbosses, and a cylindrical electrical contact in said cavity having acircumferential recess and a rearwardly facing shoulder in opposedrelationship to said shoulders on said bosses, said recess being inalignment with said lip with said lip extending into said recesswhereby, upon application of a withdrawing force to said contact, saidlips are wedged between said shoulder on said contact and said shoulderson said bosses.

5. A contact retainer comprising a split cylindrical sleeve, a pair ofarms extending from opposite sides of said sleeve at one end thereof,enlarged ends on said arms extending arcuately partially around the axisof said sleeve, the edges of said enlarged ends which are roximate tosaid sleeve having inwardly turned lips, and each of said arms having aradially inwardly directed protuberance on its inner surfaceintermediate its ends, said retainer being intended for usage in acylindrical cavity having a pair of opposed bosses intermediate its endswith said sleeve disposed against said bosses on one side, with saidarms extending between said bosses, and with said lips being againstsaid bosses on their opposite sides whereby, a contact terminal havingan intermediate circumferential recess disposed in said cavity isrestrained against axial motion in one direction by the wedging effectof said lips in said recess.

6. A contact retainer comprising a cylindrical sleeve, arms extendingaxially from opposite sides of said sleeve at one end thereof, enlargedends on said arms extending arcuately partially around the axis of saidsleeve, the trailing edges of said enlarged ends which are proximate tosaid sleeve having lips directed radially inwardly towards the axis ofsaid sleeve, the leading edge portions of said enlarged ends which areremote from said sleeve being conical and divergent with respect to theaxis of said sleeve, said retainer being intended for usage in acylindrical cavity having a pair of opposed bosses intermediate its endswith said sleeve disposed against said bosses on one side with said armsextending between said bosses, and with said lips being disposed againstsaid bosses on their opposite sides whereby, a contact terminal havingan intermediate circumferential recess disposed in said cavity isrestrained against axial motion in one direction by the wedging effectof said lips between said bosses and one side of said recess.

References Cited in the file of this patent UNITED STATES PATENTS

6. A CONTACT RETAINER COMPRISING A CYLINDRICAL SLEEVE, ARMS EXTENDINGAXIALLY FROM OPPOSITE SIDES OF SAID SLEEVE AT ONE END THEREOF, ENLARGEDENDS ON SAID ARMS EXTENDING ARCUATELY PARTIALLY AROUND THE AXIS OF SAIDSLEEVE, THE TRAILING EDGES OF SAID ENLARGED ENDS WHICH ARE PROXIMATE TOSAID SLEEVE HAVING LIPS DIRECTED RADIALLY INWARDLY TOWARDS THE AXIS OFSAID SLEEVE, THE LEADING EDGE PORTIONS OF SAID ENLARGED ENDS WHICH AREREMOTE FROM SAID SLEEVE BEING CONICAL AND DIVERGENT WITH RESPECT TO THEAXIS OF SAID SLEEVE, SAID RETAINER BEING INTENDED FOR USAGE IN ACYLINDRICAL CAVITY HAVING A PAIR OF OPPOSED BOSSES INTERMEDIATE ITS ENDSWITH SAID SLEEVE DISPOSED AGAINST SAID BOSSES ON ONE SIDE WITH SAID ARMSEXTENDING BETWEEN SAID BOSSES, AND WITH SAID LIPS BEING DISPOSED AGAINSTSAID BOSSES ON THEIR OPPOSITE SIDES WHEREBY, A CONTACT TERMINAL HAVINGAN INTERMEDIATE CIRCUMFERENTIAL RECESS DISPOSED IN SAID CAVITY ISRESTRAINED AGAINST AXIAL MOTION IN ONE DIRECTION BY THE WEDGING EFFECTOF SAID LIPS BETWEEN SAID BOSSES AND ONE SIDE OF SAID RECESS.